Rotary cooler



Oct. 15, 1940. R C. NEWHOUSE 2,218,476

ROTARY COOLER Filed July 5, 1940 2 sheets-shawl Oct. 15, 1940. R QNEWHQUSE 2,218,476

ROTARY COOLER Filed July 5, 1940 2 Sheets-SheetZ Patented ct.`15, 1940`e UNITED STATES RoTAnY oooLE-R Ray C.- Newhouse, Wauwatosa, Wis.,assignor tol VAllis-Chalnlers Manufacturing Company, Milwaukee, Wis., acorporation of Delaware Application July 5, 1940, Serial No. 343,935

16 Claims.

This invention relates generally to cooling apparatus and moreparticularly tothe construction and operation of rotary coolingapparatus adapted for use in cooling iron oxide, cement clinker, etc.,hereinafter referred to as clinker.

The cooling of clinker with apparatus of this Y type is generallyeffected by passing air through `the interior of the rotary cooler in acounter flow direction with respect to the travel of the clinkertherethrough. The cooling airwhich is heated in passing through thecooler is either all discharged into the usual kiln connected with theclinker inlet end of the cooler or a `portion of the air after leavingthe cooler -is discharged into the kiln and the remainder is dischargedto'at- Inosphere through an independent stack. 'Ihe usual practice is toeffect a compromised con-` struction which dispenses vwith the use of anindependent stack, but which necessitates employing far too much air forgood combustion eiciency and not enough air for the desired degree ofcooling. n

The discharge of all of thecooling air into the kiln results in either agreat excess of air in the kiln and inefficient combustion oran-insufcient cooling of the clinker. For example, if the quantity ofair normally required for cooling purposes is reduced so as to becommensurate with that required for efficient combustion within thekiln,the clinker is insufficiently cooled since the relatively small quantityof air required for eflicient combustion within the kiln is quicklyheated sufciently upon entering the cooler to rei duce, to anundesirable degree, the difference in temperature between the air andthe clinker to be cooled thereby. The air normally required for coolingpurposes leaves the clinker inlet end of the cooler at a temperature of-a few hundred degrees F. and if all of this air enters the kiln, thering rate must be materially increased in order to offset the coolingeffect of the great excess of relatively cool air entering` the kiln,far

too much air is present for good combustion eff ficiency, andthe heatimparted tothe air in passing throughthe kiln is wasted since the airupon leaving the` kiln is discharged directly to atmosphere through asuitable stack structure. e

The division of the heated cooling air leaving the clinker inlet end ofthe cooler between Han ai independent stack and the kiln does avoidintroducing an undesirable excess of air into the kiln, but the overallefficiency is not greatly `improved since the major portion of the airwhich has been heated to a temperature of few hundred degrees t? F. iswasted by being discharged through the 'stack to atmosphere, and therelatively smallpor- `tion of this air which enters the kiln is notheated when; it leaves the cooler to a temperature conducive to goodcombustion eliiciency andtherefore requires further `heating within the5 clinker discharge or ringend of the kiln. More--` over, there is not asufficient diiference between the temperature of the air and the clinkerat the f clinker inlet end of the cooler to effect a sudden cooling or achilling of the clinker at this point which is necessary in connectionwith the clinkering and cooling of iron oxide and similar substances inorder to avoid overheating and damage to the clinker inlet end portionof the cooler.

An object of this invention is to provide an improved rotary coooler andkiln arrangement.

Another object of this invention is to provide an improved rotary coolerand kiln arrangement which is efficient and which adequately vcools theclinker without introducing excess air into the kiln.

Still another object of this invention is to provide an improved rotarycooler construction. Still another object of this. invention is toprovidel an improved arrangement for Vflowing air through a rotary typecooler in order to improve the eiiciency of the cooler.

Still another object of this invention is to pro- *vide an improvedrotary cooler construction in `that an intermediate portion of thecooler embodies a novel and improved correlation of air passage andclinker conveying means. y

A further object of this invention is to provide an improved rotarycooler construction in that an intermediate portion ofthe cooler isprovided with a partition means operable to prevent a continuous iiow ofair throughout the length of the cooler and with an enclosed clinkerconveying means operable to convey the clinker through said partitionmeans;

The invention accordingly consists of the various features ofconstruction, combinations of elements and arrangements of parts as morefully set forth in the appended claims and in the detailed description,in which: v 45 Fig. 1 schematically illustrates a rotary clinker coolerand kiln arrangement embodying the invention;

Fig. 2 is a detail view, partly in section, schematicallyillustratingthe arrangement of the enclosed clinker conveying and airwithdrawal means;

Fig. 3 is a transverse section taken on line III- III of Fig. 2 with theclinker conveying means 55 omitted to better show the arrangement of theair withdrawal openings;

Fig. 4 is an axial perspective View of the interior of a section of thecooler taken on line IV--IV of Fig. 2;

Fig. 5 is a partial sectional View taken on line V-V of Fig. 4;

Fig. 6 schematically illustrates a modified rotary clinker cooler andkiln arrangement which also embodies the invention; and

Fig. 7 is a detail view, partly in section, schematically illustratingthe arrangement of the enclosed clinker conveying and air Withdrawal andadmission means shown in Fig. 6.

Referring to Fig. 1 it is seen that the arrangement which isparticularly adapted for clinkering and cooling iron oxide and similarmaterials comprises an inclined rotary clinker cooler l, a kiln 2, afiring hood and clinker receiving means 3 for directing the hot clinkerdischarged from thekiln into the adjacent open end of the cooler lI, anair withdrawal means 4, a burner pipe 5,

a secondary air conduit 6, and a cooling air supply pipe 1.

The cooler i, which is supported for rotation about its longitudinalaxis by means of the axially spaced supporting roller structures 8 andwhich is slowly rotated on said supports by means of a driving motor(not shown) yopera-` tively connected with the usual annular gear 9,includes, asbest shown in Figs. 2 4, inclusive, an intermediate portionprovided with an annular series of circumferentially spaced airWithdrawal openings i@ and an enclosed clinker conveying means il. y

Acombined Astack and casing structure i2, which encloses the saidintermediate portion of the cooler, is provided with a partition i3dividing the interior of the stack and casing structure above the coolerinto two upward extending ducts or passages tl and i5 which merge into acommon passage prior to reaching the top oi the stack. The top portionof the stack is provided with a draft regulating damper i6. A blower l'lhas its inlet i8 operatively connected with the v,duct l5 and its outlett9 operatively connected to discharge the air withdrawn from the duct l5through a fuel and air mixing device and through the secondary airpipe'. A

4suitable fuel is supplied to the mixing device 20 which is connectedwith the burner pipe 5, through a pipe 2l and the mixing device 2d andthe pipe 5 are arranged in parallel flow arrangement with respect to thesecondary-air pipe 6. Valves 22 are provided for separately varying theiioW of primary air to the mixing device 2t and the iiow of secondaryair through the pipe The partition I3 is provided with a valve means 23for increasing the quantity of relatively cool air which passes from theintermediate zone, through the openings lll and into the duct l5 whichin turn permits the highly heated air from the clinker inlet end of thecooler, which has already been tempered to some degree in the saidintermediate Zone by mixing with some of the relatively cool air comingfrom the clinker discharge end of the cooler, to be further tempered ifnecessary to the desired degree before enteringthe fan il. In thisconnection, it is preferable that the arrangement be such that, undernormal conditions, the highly heated air from the clinker inlet end ofthe cooler be tempered suilcientlyin the said intermediate Zone toprevent overheating and damage to the blower and to'prevent preignitionand burning of the combustible mixture within the mixing device and/orthe burner pipe 5. However, in order to permit a variable tempering ofthe air within the duct i5 which may be necessitated due to Variabledraft conditions, the provision of means such as the valve means 23 orany other functionally equivalent apparatus is desirable.

The enclosed clinker conveying means l l comprises a pair of axiallyspaced transversely disposed clinker retaining rings 24 definingtherebetween a zone in which is disposed the air withdrawal openings itand a plurality, three in this instance, of circumierentially spacedclosed clinker conveying tubes 25 of helical form which extend throughsaid zone adjacent the inner surface of the cooler and through theclinker retaining rings 24. The inlet end portion of each tube 25 afterpassing through the partition nearest the inlet end of the cooler coactswith the outer surface thereof with respect to said Zone and with theinner surface of the clinker cooler, as best shown in Figs. 4 and 5, andforms therewith an enlarged inlet or scoop portion 25. The discharge endportion of each tube 25 after passing through the partition nearest thedischarge end of the coolei` terminates closely adjacent the outersurfacethereof with respect to said zone, Vas best shown in Figs. l and2. No enlargement of the discharge end of the closed clinker conveyingtube is necessary.

The hot clinker entering the cooler moves slowly toward the clinkerretaining ring 24 which is nearest the inlet end of the cooler and uponreaching this ring is scooped into the enlarged inlet portion 26 of thetubes 25 due to the rotation of the cooler. The inclination and rotationof the cooler and the helical formation of the tubes causes the clinkerto thereafter pass through the tubes from which it is discharged at apoint immediately rearward of the partition 24 which is nearest thedischarge end of the cooler. The axially spaced rings 2d function toprevent unconned clinker from entering the Zone intermediate the saidaxially spaced rings and the only clinker entering the said Zone andpassing therethrough is that which is confined Within the closed clinkerconveying tubes 25. rlhe rate at which the clinker moves axially throughthe cooler is primarily dependent upon three factors, namely, (l) theinclination of the cooler, (2) the speed at which the cooler rotates,and (3) the type of clinker conveying means employed; i. e., theinterior surfaces of rotary coolers are usually provided with clinkerimpelling projections or the like which have been omitted from thedisclosure in the interest of simplicity. Consequently, the annularretaining rings 24 and the closed clinker conveying tubes 25 must be sospaced and dimensionecl, taking into consideration the above mentionedthree factors, that the clinker does not pile up in front of the clinkerretaining ring nearest the inlet end of the cooler and flow over thisring and into that portion of the cooler which is intermediate theaxially spaced retaining rings 24 and which contains the air withdrawalopenings I0. The proper arrangement and the dimensions of the airwithdrawal openings IQ, the retaining ringsy 24 and the conveying tubes25 are purely a matter of design which can be readily determined for anyparticular application by any one skilled in the art and further detailsin this connection or the dimensions actually used in a particularapplication are not deemed necessary for a complete understanding of thepresent invention. l

rIhe cooling air which enters the cooler through the open clinkerdischarge end thereof and that which enters the inlet end of the cool-erthrough the pipe 'I is caused to flow toward and into the zone which isintermediate t-he said :axially spaced retaining rings 2d land outthrough the :air withdrawal openings It :therein by the action of thestack structure I2 and by the opera-tion of the blower il. The ilow oflair into the cooler Ithrough Ithe pipe l, the primary function of whichis to effect a sudden cooling or a chill-ing of .the incoming clinkenmay be effected entirely by the action lof the stack structure I2 andoperation of the blower l 1 or if desired, this action may besupplemented lby .asecond blower (not shown) arranged to discharge airinto the pipe l.

The simultaneous intro-duction of unheated air into the opposite endsofthe cooler yand the withdrawal of the heated cooling air from a commonzon-e intermediate the said ends effects a sudden cooling or chilling ofthe -clinker -as it enters the cooler thereby preventing *overheatingand damage to the clinker inlet end of the cooler. 'The cooling airentering the clinker inlet end of the cooler becomes highly heated bythe time it reaches the intermediate zone containing the air Withdrawalopenings I6. Therefore some degree of tempering is usually necessary aspreviously mentioned in order to avoid loverheating and damage to theblower l1 and to prevent preigniton within the mixing device 2l] and/orburner pipe 5.

The tempered I'air which is withdrawn from the duct I5 by the blower VIis used as primary air in forming `a combustible mixture which isdischarged through the burner pipe 5 land is burned within the kiln 2:and las secondary lair which is discharged through the pipe Ci .andinto the kiln 'to support `and complete .the combustion of the fuel andair mixture introduced .through the burner pipe 5. The quantity ofsecondary air is regulated by the valve 22 in the pipe E and also by thestack damper I6, the position oi which will also vary to some extent:the quantity of .tempered .air withdrawn lfrom the duct I5 in the stackstructure I2 by the blower Il. rlhis ar- -rangement permits la properregulation of the quantity oi primary and secondary air discharged intothe kiln, which in turn permits the quantity of excess :air in the kilnto `be reduced tothe minimum commensurate withefhcient combustion underall operating conditions. The quan-- tity of air passing through thekiln is always a minimum and therefor-e the quantity of `highly heatedai-r which is discharged from the kiln through .the usual stackstructure (not shown) and wasted is also -a minimum. Consequently, theoverall efficiency of the disclosed rotary clinker cooler land kilnarrangement is materi- Ially increased. l l

Referring to Figs. 6 .and `'7, in which like numer als :are used todesignate the same or similar parts, it is seen that this m-odincation,which is particularly adapted for clinkering `and cooling cement andsimilar material-s, differ-s from the arrangement shown in Figs. `l5,inclusive, in that .the lcooling air supply pipe 1, the stack partitionI3, and the valve means 23 are omitted; in that cooling air is admittedto the clinker inlet end portion of the cooler I through an annularseries of circumferentially spaced air inlet openings 2'! and flowsforward through the clinker inlet end portion of the cooler, then intothe er conveying tubes 25 which are also of helical form and arranged asdescribed in connection with Figs. 1 5, inclusivegextend in sealedrelation through the partition 28 so as toV prevent lair from flowingthroughout fthe entire length of the cooler; and in that the combinedstack and casing structure l2 encloses only that portion of the coolerwhich includes lthe heated air withdrawal zone 29.

'in this arrangement it is preferable that the design be such that thequantity of unheafted cooling air which enters through the openings 2l`and flows forward through the clinker inlet 'end portion of the coolerl :and then into the kiln 2 as secondary air is suliicient for goodcoin- Ibustion eiiiciency under :normal operating conditions.Consequently, except for variations in draft conditions which affect.-to some extent the quantity of air drawn into the cooler through theopenings lll, the quantity of lair which leaves the clinker inlet end oflthe cooler :and enters the kiln las secondary `air is in most instancescommensurate with eiiicient combustion requirements. However, if thedraft conditions .should be such that the quantity of `secondary lairdecreases, yadditional secondary :air can be introduced into .thefurnace simply by regulating the valve 22 in the secondary fai-r conduitl5. All of the cool-ing air which enters the -clinker discharge end ofthe cooler i-s withdrawn through the openings I by ,the action of thestack structure t2 and by the operation of the blower i?, and theport-ion of this air which is withdrawn from the stack structure i2 by:the blower il is normally used only as primary lair to form acombustible mixture; i. e., the valve 22 in the secondary lair pipe t isusually maintained in its closed position. Ii necessary, however,secondary air to supplement the secondary air ysupply which enters thekiln 2 after passing through the clinker inlet portion of the cooler lmay be introduced into the kiln through the pipe t simply by opening thevlalve 22 therein to the desired degree.

In this modioaton, the temperature of the air which leaves the clinkerinlet end of the cooler and enters the clinker discharge or firing endof the kiln as. secondary air, is commensurate with good combustioneilciency andis materially higher than the temperature of the airleaving the clinker inlet end of the cooler in the knownY arrangements,i, e., arrangements in which all of the cooling air is discharged fromthe clinker inlet end of the cooler. Therefore, no fuel is wastedinlieating the secondary air to a temperature commensurate with -goodcombustion efficiency and since the quantity of air entering the kiln assecondary air is commensurate with good combustion efficiency undernormal operating conditions, combustion eiiiciency is materiallyimproved. The overall efficiency of the kiln is further improved due tothe fact that the quantity of air passing through the kiln is always aminimum and therefore the quantity of highly heated air which isdischarged from the kiln through the usual stack structure and wasted isalso a minimum. Moreover, the temperature of the major por-tion of thecooling air which is withdrawn from an intermediate portion of thecooler and discharge through the stack structure i and wasted ismaterially less than the temperature oi the cooling air leaving theclinker inlet end of the cooler in the known arrangements and thereforethe efiiciency of the disclosed clinkering and cooling arrangement isfurther improved in this respect; i. e., the air which is actuallywasted contains less heat than the air which is wasted in the knownarrangements. Consequently, with respect to known arrangements, thismodification effects a greater increase in the eiiiciency of the coolerand in the overall eiiiciency of the rotary clinker cooler and kilnarrangement than does the arrangement shown in Figs. 1 5, inclusive, andis preferred for use in clinkering and cooling cement and similarmaterials. The particular construction and arrangement of the airwithdrawal means, the air admission means and the closed clinkerconveying means herein disclosed provides a durable and cheapconstruction which is of general application for eiecting theaforementioned im prove-d results,

The invention is obviously applicable to rotary coolers and to rotarycoolers and kiln arrangem ments of general application, and it should beunderstood that it is not desired to limit the invention to the exactmode oi operation and to the exact details oi construction herein shownand described, as modifications within the scope of the claims may occurto persons skilled in the art.

It is claimed and desire-d to secure by Letters Patent:

l. In combination, a kiln, a rotary cooler arranged to receive and toconduct therethrough the clinker discharged from said kiln, said coolerhaving an intermediate portion provided with axially spaced clinkerretaining rings, with one or more air passage openings in the wall ofthe cooler between said retaining rings, and with an enclosed clinkerconveying means extending through said rings and the zone formedtherebetween, means operable to introduce cooling air into a portion ofsaid cooler remote from said openings, means including said openingsoperable to withdraw the air which has been introduced into said remoteportion oi the cooler, and means operable to deliver Iair withdrawnthrough said openings into said kiln.

2. In combination, a kiln, a rotary cooler arranged to receive and toconduct therethrough the clinker discharged from said kiln, said coolerhaving longitudinally spaced portions into which cooling air isadmitted, and an intermediate portion provided with axially spacedclinker retaining rings, with one or more air passage openings in thewall of the cooler between said retaining rings, and with an enclosedclinker conveying means extending through said rings and the zone formedtherebetween, means including said openings operable to withdraw the airwhich has been introduced into said longitudinally spaced portions ofthe cooler, and means operable to deliver air withdrawn through saidopenings into said kiln.

3. In combination, a kiln, a rotary cooler arranged to receive and toconduct therethrough the clinker discharged from said kiln, said coolerhaving yan intermediate portion provided with axially spaced clinkerretaining rings, with one or more air passage openings in the wall ofthe cooler between said retaining rings, and with an enclosed clinkerconveying means extending through said rings :and the zone formedtherebetween, means for introducing cooling air into said cooleradjacent the clinker inlet and discharge ends thereof, means operable towithdraw the air admitted to said cooler through said openings, andmeans for delivering air withdrawn from said cooler into said kiln.

Li. In combination, a kiln, a rotary cooler arranged to receive and toconduct therethrough the clinker 1discharged from said kiln, said coolerhaving an intermediate portion provided with axially spaced clinkerretaining rings, with a partition means disposed between and in axiallyspaced relation with respect to said spaced retaining rings and dividingthe interior of the cooler into non-communicating front and rearportions, with one or more air passage openings in the wall of thecooler between each clinker retaining ring and said partition means, andwith an enclosed clinker conveying means extending through said ringsand partition means and through the Zones formed therebetween, meansoperable to introduce air into the rear portion of said cooler at apoint remote from said partition means and into the iront portion ofsaid cooler through the opening disposed between said partition meansand the clinker retaining ring disposed forwardly thereof, meansincluding the opening in the rear portion of the cooler between saidpartition means and the clinker re.- taining ring ,disposed rearwardlythereof operable to withdraw the air introduced into the rear portionof-the cooler, and means operable to deliver air withdrawn through saidopenings into said kiln.

5. In combination, a kiln, a rotary cooler arranged to receive and toconduct therethrough the clinker discharged from said kiln, said coolerhaving an intermediate portion provided with axially spaced clinkerretaining rings, with a partition means disposed between and` in axiallyspaced relation with respect to said spaced retaining rings and dividingthe interior of the cooler into non-communicating front and rearportions, with one or more air passage openings in the wall of thecooler between each clinker retaining ring and said partition means, andwith an enclosed clinker conveying means extending through said ringsand partition means and through the zones formed therebetween, meansoperable to introduce air into the rear portion or said cooler at apoint remote from said partition means and into the front portion ofsaid cooler through the openings disposed between said partition meansand the clinker retaining ring disposed forwardly thereof, and meansincluding the opening in the rear portion of the cooler between saidpartition means and the clinker retaining ring disposed rearwardlythereof operable to withdraw the air introduced into the rear portion ofthe cooler.

6. In combination, a kiln, a rotary cooler arranged to receive and toconduct therethrough the clinker discharged from said kiln, said coolerhaving an intermediate portion provided with axially spaced clinkerretaining rings, with a partition means disposed between and in axiallyspaced relation with resp-ect to said retaining rings and dividing theinterior of the cooler into non-communicating iront and rear portions,with one or more air passage openings in the wall of the cooler betweeneach clinker retaining ring and said partition means, and with anenclosed clinker conveying means extending through said `the clinkerdischarge end of the cooler and to 'rings and partition means andthrough the zones formed therebetween, means operable to introduce airinto the cooler throughthe openings in the front portion of the coolerbetween said partition means and the clinker retaining ring disposedforwardly thereof and to cause the air thus admitted to flow forwardlythrough the front portion of the cooler and into said kiln, meansoperable to introduce air into azone in the rear portion of the coolerat a point remote from said partition means, and means including theopening disposed inthe rear portion of the cooler between said partitionmeans and the clinker retaining ring disposed rearward thereof operableto withdraw the air introduced into the rear portion of the cooler.

7. In combination, a kiln, a rotary cooler arranged to receive and toconduct therethrough the clinker discharged from said kiln, said coolerhaving an intermediate portion provided with axially spaced clinkerretaining rings, with a partition means V disposed between and inaxially spaced relation with respect to said retaining rings anddividing the'interior of the cooler into noncommunicating front and rearportions, with one or more air passage openingsin the wall of the coolerbetween each clinker retaining ring and said partition means, and withan enclosed clinker conveying means extending through said rings andpartition means and through the Zones formed therebetween, meansoperable to introduce air into the cooler through the opening in thefront portion of the cooler between said partition means and the clinkerretaining ring disposed forwardly thereof and to cause the air thusadmitted to flow forwardly through the front portion of the cooler andinto said kiln, means operable to introduce air into a zone in the rearportion of the cooler at a point remote from said partition means, meansincluding the opening disposed in the rear portion of the cooler be,

tween said partition means and the clinker retaining ring disposedrearward thereof operable to withdraw the air introduced into the rearportion of the cooler, and means operable to deliver a portion of theair withdrawn through said opening into said kiln.

8. In combination, a kiln, a rotary cooler arranged to receive and toconduct therethrough the clinker discharged from said kiln, said coolerhaving an intermediate zone operatively connected with an airwithdrawing means and means for confining and for conveying the clinkerthrough the said intermediate Zone, means operable to introduce coolingair into the clinker inlet and discharge end portions ofthe cooler atpoints remote from said intermediate Zone, and

' having an intermediate portion provided with axially spaced openingsin the wall thereof, with r a partition means disposed between saidspaced openings and dividing the interior of the cooler l into front andrear portions each having an openycooler through the opening in saidfront portion and to cause air thus admitted to flow forward through thesaid front portion and into said kiln, and means operable to introducecooling air into cause the air thus introduced to flow forwardly throughsaid rear portion and out through thev opening in the forward end of thesaid rear portion.

10. In combination, a kiln, a rotary cooler arranged to receive and toconduct therethrough `means including a second opening in said rearportion operable to cause cooling air to now into the rear end of saidrear portion, then forward toward said partition means and then out ofthe cooler 'through said second opening.

11. In combination, a kiln, a rotary cooler arranged to receive and toconduct therethrough the clinker discharged from said kiln, said coolerhaving an intermediate zone provided with an enclosed clinker conveyingmeans extending therethrough, means including a first opening in theforward portion of said intermediate zone operable to cause cooling airto iiow into the forward portion of said zone and then forward throughthe cooler and into said kiln, and means including a second openinginthe rear portion of said intermediate zone operable to cause coolingair to flow into the clinker discharge end of the cooler, then forwardtoward the rear portion of said intermediate zone and then out of thecooler through said second opening.

12. A clinker cooler comprising a rotary shell having clinker inlet anddischarge end portions and an intermediate portion provided with axiallyspaced clinker retaining rings, with one or more openings in the wall ofthe shell between said spaced clinker retaining rings, and withanenclosed clinker conveying means extending through said clinkerretaining rings and the Zone formed therebetween, and means operable tocause cooling air to flow into the shell through said end portions andout through the openings in said intermediate portion.

13. A clinker cooler comprising a rotary shell having clinker inletanddischarge end zones and an intermediate zone provided with one ormore air passage openings and with an enclosed clinker conducting meansextending through said intermediate zone, and means operable to causecooling air to flow into the shell through said end zones and outthrough the openings in said intermediate zone.

14. A clinker cooler comprising a rotary shell having clinker inlet anddischarge end portions and an intermediate portion provided with firstand second air passage openings separated by a partition means dividingthe interior of the shell into non-communicating front and rear portionsand with an enclosed clinker conveying means extending through saidpartition means and beyond saidopenings, means including said firstopening operable to cause cooling air to flow into the rear end of saidfront portion, forward therethrough and out through said inlet end, andmeans including said second opening operable to cause cooling air toflow into the rear end of said rear portion, then forward toward saidpartition means and out through said second opening.

15. A clinker cooler comprising a rotary shell having clinker inlet anddischarge end openings, a partition dividing the interior of the shell'into non-communicating front and rear portions, and having an enclosed@linker conveying means extending frointhe rear end of said frontportion, through said partition means and into the front end of saidrear portion, means including a front opening in said shell operable tocause cooling air to flow into the rear end of said front portion, thenforward toward said inlet end and then out of the shell, and meansincluding a second openasians ing in said shell operable to causecooling air to flow into the rear end of said rear portion, then forwardtoward said partition and then out of the shell.

16. A clinker cooler comprising a rotary clinker conveying shell havinga partition dividing the interior of the shell into non-communicatingfront and rear portions, having means including openingsin said shelloperable to cause a simultaneous ow of cooling air through said frontand rear portions, and having an enclosed cinker conveying meansextending through the said partition.

RAY C. NEWI-IOUSE.

